Speed control systems such as cruise control systems and adaptive cruise control systems (ACC) are common on vehicles. Even car owners who do not have speed control systems in their own vehicles are typically familiar with such devices and often easily implement the use of the speed control systems when using vehicles with such systems. Drivers often find it convenient to set a desired speed for the vehicle and allow the speed control system to maintain the speed of the vehicle at the set speed. However, existing speed control systems still require a relatively substantial amount of input from the driver to alter the speed of the vehicle. For example, when a speed limit changes from one speed to another, for example, from 50 miles per hour to 65 miles per hour, and the speed control system was previously set to maintain a vehicle speed of just below 50 miles per hour, the driver must affirmatively change the set speed of the vehicle control system to increase the vehicle speed. For example, if the vehicle control system was set at just below 50 miles per hour to comply with the posted speed limit of 50 miles per hour the vehicle will continue to drive at just under 50 miles per hour unless the driver takes some action. By way of a further example, traffic conditions may change such that the driver who is driving below the posted speed limit due to congestion should increase the vehicle speed once the congestion on the roadway has been relieved. If, for example, the driver is driving in a high traffic area where the posted speed limit is 55, but the density of vehicles on the roadway will only permit the driver to drive at 40 miles per hour and the driver sets the speed control system to 40 miles per hour, once the traffic condition changes such that the cars around him may again safely travel at (or under) the posted speed limit of 55 miles per hour, the driver must affirmatively change the speed setting of the speed control system to increase the speed of the vehicle.
Thus, there was need for a speed control system that better interacts with a changing vehicle environment. Such a need is fulfilled, at least in part, by the cooperative speed control systems disclosed in co-pending U.S. patent application Ser. Nos. 11/094,347, 11/094,844 and 11/094,799 filed on Mar. 31, 2005, respectively entitled Cooperative Speed Control System, System and Method For Timing of Target Speed For Cooperative Speed Control System, and System and Methods Utilizing Slope of Target Speed For Cooperative Speed Control System, all three applications by the present inventors, the contents of which are incorporated herein in their entirety. Those applications detail methods, apparatuses and systems for controlling vehicle speed that better interacts with a changing vehicle environment including methods, systems and apparatuses for automatically decreasing and increasing vehicle speed.